Through radical copolymerization, the soluble copolymer dispersant AA/SAS for ceramic powder was synthesized with acrylic acid (AA) and sodium allylsulfonate (SAS). The effect of different reaction conditions on the dispersing property of copolymer has been investigated. The copolymer was analyzed by Fourier transform infrared spectrometer (FTIR), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and gel permeation chromatography(GPC). Meanwhile, the effects of dispersant concentration on the rheological behavior and Zeta potential of the ceramic slurry were also studied. The results show that the optimum condition of synthesis is as follow: the mass ratio of acrylic acid and sodium allylsulfonate 5:1, the reaction temperature 80℃, the dosage of initiator 7.3%, and the amount of chain transfer agent 225.5%. When its mass fraction was 0.3%, its dispersing effect was the best. The Zeta potential absolute value of the slurry increased from 33.7mV to 62.1mV as the mass concentration of the copolymer was 1.2g/L. In comparison with imported products PC-67, the copolymer could show better dispersity．